U2 Clone Emitter Swap- K2 to SSC P4- now w/ beamshots!

aileron

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So my clone U2 arrived today.


In another package was a SSC P4 emitter and some AA epoxy. Guess what comes next? :D



Here's the stock K2. Unfortunately my pliers slipped while desoldering the emitter and tore off the dome, killing it good and dead. Alas poor K2, we hardly knew ye.


A blob of AA later, the P4 rests securely in its new home.

As for the light itself, I'm quite happy with it.
With a wipe and some nyogel the threads are silky smooth. Anodizing is dark and even. Has a smooth plastic reflector and a glass lens.
If they ditched the SF logos and the selector ring, it'd be just about perfect.

ETA: As per pics below, the two-stage design is achieved by a three pole switch with a resistor tied across it. The pill itself is devoid of electronics, despite containing a PCB. It looks like there's maybe 5mm of wasted depth in there, same width as the star. If you replaced the PCB and positive spring, you could probably get a full centimeter of depth.

Wonder what drivers would fit in there..

ETA2: Beamshots!

First my P1D CE on High (Turbo).


Now the U2 Clone on a partially depleted DLG 18650. As you can see, the emitter isn't perfectly centered in the reflector. To be honest I hadn't noticed until now.


Since some people seem to like them, here's a 16color gif of the P1DCE.


..and one of the SSC.

ETA3: Just realized someone will probably want to know the details of the pics.
I took them with a Pentax *ist DL- lens@18mm, 1/180s, f/4.0, ISO 800. The lights were about 3ft from the ceiling, that was the largest unblemished painted space I could find.
 
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bombelman

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Re: U2 Clone Emitter Swap

Nice, nice...

Let us know the result...

BTW, what internals does it have ? Regulated ? Can you swap the board and still keep the swicht mechanism ?
 

EngrPaul

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Re: U2 Clone Emitter Swap

It would be good to check the current. K2's are typically overdriven to a couple amps.

Was the original star thermally wetted (epoxy or compound) to the base?
 

aileron

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Re: U2 Clone Emitter Swap

bombelman said:
Nice, nice...

Let us know the result...

BTW, what internals does it have ? Regulated ? Can you swap the board and still keep the swicht mechanism ?

Looking around through the little hole in the pill:

I can see the blue positive wire seems to be soldered directly to the spring on the underside of the pill.
Removing the switch, one sees this:

Unscrew the plastic collar and that metal slug comes out to reveal the spring:

Unscrew the metal collar, and the switch itself is released.

As you can see it's a resistored setup, looks easy enough to modify.
 

aileron

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Re: U2 Clone Emitter Swap

EngrPaul said:
It would be good to check the current. K2's are typically overdriven to a couple amps.

Was the original star thermally wetted (epoxy or compound) to the base?

The star had some sticky thermal compound between it and the slug, but I wiped most it off before I took pics. You can see a bit of the remains above.
I think the light is unregulated on high, so likely not driven nearly as hard as some K2s.
 

EngrPaul

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Re: U2 Clone Emitter Swap

Thanks for he reply about the thermal compound. :grin2: It needs to be there because heat doesn't jump across air very efficiently, and without the compound the star only touches the base in a few small places.
 

aileron

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Re: U2 Clone Emitter Swap

EngrPaul said:
Thanks for he reply about the thermal compound. :grin2: It needs to be there because heat doesn't jump across air very efficiently, and without the compound the star only touches the base in a few small places.

I'm pretty sure just air would've produced more efficient conduction than the uneven streaks of goop that were there. :sick2:
But your point is well taken, I should put a little AS on there.
 

aileron

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Re: U2 Clone Emitter Swap- K2 to SSC P4

matrixshaman said:
Was this light made to take 1 x 18650, 2 x CR123's or 2 x RCR123's?

It was designed for an 18650- as it's unregulated on high, two Li cells would promptly murder the stock K2.
 

Mike M

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Re: U2 Clone Emitter Swap- K2 to SSC P4

I uses 2 123 cells in mine and have had no problems. Why do you think they would murder the K2?
 

cratz2

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Re: U2 Clone Emitter Swap- K2 to SSC P4

I assumed he meant that two LiIon (2xR123As) would kill the star... not two primary/non-rechargeable CR123As.

I don't have the light so I am only guessing though...
 

Mike M

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Re: U2 Clone Emitter Swap- K2 to SSC P4

2 123 cells fit in the light fine. I have never held a 18650 but it looks bigger than and 123 by pictures I have seen. I'm thinking one 18650 cell will not be long enough and even with a dummy cell the light wouldn't be bright enough. 2 18650's, I'm thinking, will be too long and would likely blow the LED. I haven't had the light long but I have already used up one pair of regular 123 cells with no problem.
 

aileron

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Re: U2 Clone Emitter Swap- K2 to SSC P4

Sorry guys, I should've been more specific.

As you can see in the first pic, the light says it should be fed with one 18650.
The highest K2 Vf I can see in the datasheet is 5v for the 1A binned parts, so I suppose direct drive off 2x123 primaries wouldn't kill it swiftly as I assumed earlier. Note though that the highest nominal K2 Vf I can see is 3.72V.
A BS primary holds above 2.5V for most of its life at .5A draw, so you'd be pretty close to the max Vf. An R123 will hold above 3V, putting you over the top.

In comparison, the SSC emitter I have in there now has a nominal Vf of 3.2V and a maximum of 3.8V. It plays nice with an 18650, but two primary 123s turns it angry blue.

Also Mike, a 123 is 16340 (16mm/34mm), very close to one half the length of the 18650 (18mm/65mm). Two 18650s would require a 4x123 length body, and would face the same problem as the R123s mentioned above- a combined voltage above 6v.
 

Prototype3a

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Re: U2 Clone Emitter Swap- K2 to SSC P4

I'm considering this light/mod.. where and which SSC led did you get? Have you noticed any change in the runtime?
 
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Ganp

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Re: U2 Clone Emitter Swap- K2 to SSC P4

Nice job on the P4 upgrade and the photo's. :twothumbs

I bought one of these out of curiosity to see if it was worth modding, and I really don't like that they had marked it as Surefire. :scowl:

However, I have used it with 18650's, and 2 x rechargeable 123's and the K2 is OK so far.

Colin.
 

cratz2

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Re: U2 Clone Emitter Swap- K2 to SSC P4

Another thing just to throw out there... primary CR123As have quite a bit more internal resistance than LiIon cells so the effective 'power' from them is less. For example, 2x17500 cells (7.4V through most of their discharge) drives a bulb about as hard as 3x123 cells (9V through most of their discharge).

Actually, I'd expect a direct driven LED light to be a bit brighter on 1x18650 than on 2 CR123As for most of the discharge.
 

aileron

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Re: U2 Clone Emitter Swap- K2 to SSC P4

Prototype3a said:
I'm considering this light/mod.. where and which SSC led did you get? Have you noticed any change in the runtime?

Both the SSC P4 emitter and the AA epoxy came from PhotonFanatic's bighuge sale thread. It contains many goodies.
I ran the stock K2 for perhaps 30 seconds before dismantling the light and I'm using unprotected cells atm, so unfortunately I can't say about K2 vs P4 runtime. :(
 
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